To provide fuel for motorized vehicles, there are numerous fuel outlet sites located throughout the industrial world. During recent years, there has been a trend toward the vehicle operator performing the fueling operation at so-called self service fueling sites. Often these self service fueling sites have a specialized fueling system where the dispensers are controlled by a remote dispenser control system. Generally, the dispenser includes a pump, a fuel supply nozzle, a flowmeter, a flow quantity signal generator, and a flow indicator. The pump has at one end a pipe connection to a fuel supply tank, and at the other end a hose connection to a fuel supply nozzle. The flowmeter measures the quantity of fuel being pumped, and the flow quantity generator generates a flow quantity signal from the flowmeter. The indicator indicates the quantity of fuel being pumped based on the flow quantity signal.
Typically at self service fueling sites, the dispensers are controlled by a remote dispenser control system located in a building at the fueling site, allowing the site attendant to control dispenser operation. The dispenser control system has electrical connections to the dispensers for transferring data signals. Generally speaking, the control system is a microcomputer for controlling dispenser function. The microcomputer has read-only-memory (ROM), read-and-write-memory (RAM), and input/output ports such that it can store information or read information applied at the ports. Specific functions of the control system microprocessor are well known to those skilled in the art. U.S. Pat. No. 4,550,859 relates to a microprocessor controlled system for controlling fluid dispensing pumps.
The microprocessor based dispenser control system may be in the form of a stand alone console, or it may be in the form of a logic module which interfaces with an electronic cash register or point-of-sales system. However, the principles involved are the same. While examples in this specification relate to a stand alone console, it is understood that the present invention relates to all remote dispenser control systems including consoles, point-of-sales interfaces, and card readers.
The dispenser control console sends data signals to the dispensers, and the dispensers sends data signals to the console. Data signals sent to the dispensers from the console include price per gallon to be charged at corresponding pumps, preset limits to be pumped at corresponding pumps, and pump authorization. Data signals sent from the dispensers to the console include pump identity (pump number), pump status, and dispensed fuel volume and value. Fuel volume may be for a single transaction, or totals for a given time period depending on the information requested by the console operator.
Briefly, the present invention relates to a data signal monitoring system for monitoring data signals in a data wire without interrupting signal flow. In the illustrative embodiment, the data signal monitoring system is connected to the data wires between the dispenser and control console. The design is such that data signals are monitored without interrupting the communication between the console and dispenser. The monitoring system interprets the data and analyzes pump status and commands. The monitoring system translates the data signals into serial signals which are sent to a microprocessor for processing. The microprocessor can then control other devices from information extracted from the communication between the dispensers and console.
All data signals between the dispensers and console enter the data signal monitoring system. It is desirable, however, to select certain data signals for processing, and to discard other data signals. This is accomplished by a program switch selector which instructs the microprocessor as to which signals to process, and which signals to discard. In a preferred embodiment of the illustrative example, the microprocessor extracts information relating to the price per gallon of the fuel, and relates this information to a large display sign at the fueling site so that potential customers can see the price of the fuel from a distance. In an alternate embodiment, the microprocessor extracts information relating to fueling process, i.e., it generates an output signal for indicating when the customer lifts the nozzle and activates the pump. This information may be used to activate audio devices, for example, instructions on the dispensing process or promotional messages. These are, however, to be taken as illustrative examples in that data can be extracted and used to control other devices relating to the fueling process.